Field of the Invention
The present invention relates to a technique of analyzing the behavior of a print medium transported through the conveyance path of an image forming apparatus or the like and supporting conveyance path design.
Description of the Related Art
When designing a print medium conveyance path in a printer, the functions of designed structures are examined under various conditions. This makes it possible to decrease workloads needed to manufacture and test prototypes and reduce the development period and cost. For this purpose, a design support system for simulating the behavior of paper in a conveyance path has been proposed. The design support system expresses paper by finite elements of the finite element method (FEM), determines the contact between the paper and a transport guide or feed rollers in the conveyance path, and numerically solves equations of motion, thereby evaluating the transport resistance or contact angle between the paper and the transport guide. In addition, a method of more simply expressing paper by a mass and a spring, thereby improving the calculation speed has been made open (for example, literature 1).
Literature 1: Katsuhito Sudan, “Modeling a String from Observing the Real Object”, Proceedings of 6th International Conference on Virtual Systems and Multimedia (VSMM2000), pp. 544-553, 2000
To solve a motion of paper, the Euler method, Newmark β method, Wilson θ method, and the like are known. According to these methods, equations of motion of paper discretely expressed by finite elements or a mass-spring system are formulated. The analysis time is divided into time steps each having a finite width, and numerical time integration for sequentially obtaining the acceleration, speed, and displacement that are unknowns is performed in each time step from time zero.
In the design support system, as a representative method of verifying simulation results, deformation behaviors of paper on animation display or graphic display is observed. The deformation state of paper can be grasped by the observation, and factors of design deficiencies such as paper caught on an uneven portion of the conveyance path, a folded corner of paper, and paper jam can effectively be identified.
Japanese Patent Laid-Open No. 2010-072853 proposes a method of effectively displaying behaviors of a portion (a tip of paper, or the like) under focus of an operator using 3D simulation display with analysis contents more complex than 2D simulation display, aiming at preventing oversight of design deficiencies and reducing a work load.
However, it is difficult to evaluate design problems (print accuracy and the like) to cope with high-quality printed products of recent demand only by observing behaviors of a portion under focus of the operator. In the conveyance path from paper feed to discharge, paper is simultaneously fastened by a large number of feed rollers. It is therefore impossible to evaluate a small tilt or horizontal deviation of paper only by observing simple animation display or paper track. In other words, it is impossible to quantitatively grasp how a slight transport deviation of a print medium changes and specify the location where an error occurs, and factors of the error.
The design support system can detect a failure on the path, for example, paper caught on the transport guide or paper stop caused by slip of feed rollers in a path with a large transport load. However, problems of a design are not limited to visually recognizable failures. Concerning print accuracy, a small transport error of paper poses a problem.
According to the above-described simulation technique, the information of the position, orientation, and speed of paper at a certain time can be obtained. However, the information of the position, orientation, and speed of paper is not enough to obtain geometric characteristics (tilt and horizontal deviation state of paper) throughout the paper path, which are necessary to evaluate errors in steps of 0.1 mm, and specify the factors of the errors.